In a conventional flash light, it consists of a holding body, a bulb, and a reflective concave. The reflective concave is disposed at an end of the holding body. The bulb is disposed in the central bottom of the reflective concave. With the beam directly emitted from the bulb and the beam reflected by the reflective concave, the conventional flash light conducts a function of illumination. Meanwhile, the conventional flash light can change the scope of illumination by adjusting the position of the bulb on reflective concave.
However, since the technology of light emitting diode (LED) has been rapidly developed. LED, which has the advantages of high brightness and low power consumption, has gradually been applied to replace conventional bulbs. However, when an LED is applied to a flash light, due to the small size of the LED and the necessary control of circuits and heat dissipation fins, it is difficult to dispose the LED protruding from the reflective concave and change the relative position between the LED and the reflective concave so as to adjust the illumination field. In order to solve this problem, the illumination field is commonly changed by omitting the structure of the reflective concave, disposing a convex lens in front of the LED, and adjusting the distance between the convex lens and the LED.
However, the afore-mentioned flash light can merely provide a function of illumination, which is not enough for the competitive market nowadays.
Meanwhile, a conventional projector, such as a slide projector, is disposed with a slide. The image of the slide is enlarged through the convex lens and is projected onto a screen. Therefore the slide is limited to be disposed between the focus length position and the twice focus length position with respect to the convex lens. If users want to combine the technique of a projector with the flash light by placing the slide in the afore-mentioned flash light, the illumination effect will be affected by the blocking of the slide. It is troublesome for the users if they want to have the illumination effect of a flash light by manually removing the slide from the flash light.